In rotary impact tools of the type disclosed in the above mentioned patents, input, output and inertia members are journaled upon each other at mating, mutually telescoping circular surfaces for independent rotative movement about a common axis. A pawl and ratchet assembly is provided for intermittently interconnecting the input, output and inertia members together for torque transmission, the pawl being carried by the inertia member and spring biased toward engagement with the ratchet while the ratchet is connected to the output member. A power spring means interconnects the input and inertia members for storing energy upon relative angular movement of the input inertia and output members and releasing such stored energy to accelerate angular rotative movement of the inertia member when the pawl is disengaged from the ratchet. A cam is provided on the input member which coacts with the pawl upon relative angular movement of the input and inertia members to disengage the pawl from the ratchet and release the pawl for impact engagement with the ratchet to thereby rotatively drive the output member. Thus, as long as the input member is angularly moved, the escapement and impact-producing re-engagement of the pawls and ratchet occurs as a function of angular movement of the input member in overrunning or overhauling relation to the output member and inertia member. To achieve rotation of the output member in an opposite direction, the output member is provided with two output end portions each of which is alternately used to drive the member to be rotatively driven. Thus, to achieve a change in the direction of rotation, the impact tools must be disconnected and turned end-to-end to present a different end of the output member for connection to the member to be driven. This would, in the power driven tools as distinguished from the manually operated tools, require disconnection and reconnection with the source of rotative power to effect change in the direction of rotation of the output member. In addition to this shortcoming of present rotary impact tools, the tools in order to change the force of the impacts require a change in the number and/or strengths of the spring or springs to increase or decrease the spring force. To effect such force change, obviously, is time-consuming and inconvenient. These and other disadvantages of known impact tools of the type herein described are eliminated by the present invention.
It is, therefore, an object of this invention to provide a rotary impact tool of the type having a ratchet and pawl assembly which tool is capable of bi-directional impact rotative drive.
It is another object of this invention to provide a rotary impact tool, of the type having a ratchet and pawl assembly which tool is capable of being quickly and easily adjusted to deliver impacts of different magnitudes and in different direction of rotation.
Another object of this invention is to provide a rotary impact tool of the type having a ratchet and pawl assembly which is capable of driving without ratcheting action.
A still further object of this invention is to provide bi-directional rotary impact tool of the type having a pawl and ratchet assembly in which, in each direction of rotation, the force of the impacts can be varied quickly and easily without change of the force spring or springs.